Integrated circuits including dummy structures and methods of forming the same
An integrated circuit includes a core area. The core area has at least one edge region and a plurality of transistors disposed in the edge region. A plurality of dummy structures are disposed outside the core area and adjacent to the at least one edge region. Each channel of the transistors in a channel width direction faces at least one of the dummy structures.
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The present application relates generally to the field of semiconductor devices, and more particularly, to integrated circuits including dummy structures and methods of forming the integrated circuits.
BACKGROUNDThe semiconductor integrated circuit (IC) industry has experienced rapid growth. Technological advances in IC materials and design have produced generations of ICs where each generation has smaller and more complex circuits than the previous generation. However, these advances have increased the complexity of processing and manufacturing ICs and, for these advances to be realized, similar developments in IC processing and manufacturing are needed.
In the course of IC evolution, functional density (i.e., the number of interconnected devices per chip area) has generally increased while geometry size (i.e., the smallest component (or line) that can be created using a fabrication process) has decreased. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Such scaling-down also produces a relatively high power dissipation value, which may be addressed by using low power dissipation devices such as complementary metal-oxide-semiconductor (CMOS) devices.
The present disclosure is best understood from the following detailed description when read with the accompanying figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale and are used for illustration purposes only. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
In an integrated circuit, dummy patterns are disposed at a boundary region that is adjacent to a core area. The dummy patterns are configured for reducing a process loading effect and/or transistor performance variations. The inventors found that, in the edge region, channels of transistors in the channel width direction may face a blank area without any dummy pattern or functional transistor pattern. In the blank area, a shallow trench isolation (STI) structure is formed and has a large area. The STI structure strains the channel of the transistor. The strained channel affects the operation current of the transistor. Since transistors disposed in the edge region may be subjected to different strains, the operation currents of the transistors may be diversified and fall out of a predetermined specification. The strained-channel effect becomes even worse when the dimensions of the transistors shrink down.
The inventors also found that the blank area without any dummy pattern or functional transistor pattern may also induce a dual contact etch stop layer (CESL) boundary effect. During a manufacturing process, a stress layer that is configured to provide a tensile stress layer to n-type metal-oxide-semiconductor (NMOS) transistors is generally disposed in the blank area. The stress layer in the blank area can affect a tensile stress and a compressive stress respectively applied to NMOS transistors and PMOS transistors disposed adjacent the edge of the core area.
From the foregoing observations by the inventors, integrated circuits including dummy patterns and methods for forming the integrated circuits are desired.
It is understood that the following disclosure provides many different embodiments, or examples, for implementing different features of the disclosure. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Moreover, the formation of a feature on, connected to, and/or coupled to another feature in the present disclosure that follows may include embodiments in which the features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the features, such that the features may not be in direct contact. In addition, spatially relative terms, for example, “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “up,” “down,” “top,” “bottom,” etc. as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) are used for ease of the present disclosure of one features relationship to another feature. The spatially relative terms are intended to cover different orientations of the device including the features.
In some embodiments, the integrated circuit 100 is a static random access memory (SRAM) circuit, an embedded SRAM circuit, dynamic random access memory (DRAM) circuit, an embedded DRAM circuit, a non-volatile memory circuit, e.g., FLASH, EPROM, E2PROME, a field-programmable gate circuit, a digital logic circuit, an analog circuit, a mixed signal circuit, or other circuit. In some embodiments, the core area 110 includes substantially all functional devices, transistors, and circuits of the integrated circuit 100. The boundary circuit 120 may include at least one input/output (I/O) circuit.
In some embodiments, the integrated circuit 100 include a plurality of dummy structures (not shown) disposed adjacent to the at least one edge region that is adjacent to one of the edges 110a-110d. The dummy structures includes, for example, OD dummy patterns, gate dummy patterns, well dummy patterns, metal dummy patterns, other dummy patterns, or combinations thereof.
A plurality of transistors (not shown) are disposed, in some embodiments, in the at least one edge region. Each transistor has a transistor channel. Each channel of the transistors in a channel width direction faces at least one of the dummy structures. In some embodiments, each dummy structure includes one or more rows of dummy patterns. In other embodiments, each dummy structure includes one or more columns of dummy patterns. Each channel of the transistors in the channel width direction faces at least one of the row or column dummy patterns. Since each channel of the transistors is confined by neighboring dummy patterns and/or functional transistor patterns, a strain stress applied to each channel of the transistors is desirably controlled.
Referring to
In
Referring to
Referring again to
As noted, each of the channels 210a-217a is confined by neighboring dummy patterns and/or functional transistor patterns. For example, the channel 212a is confined by the OD dummy pattern 225a and neighboring patterns of the transistors 210, 211, 213, and/or 218. A strain stress applied to the channel 221a is desirably controlled. The OD spacing effect can thus be reduced. It is also found that the use of the dummy structure 240 can reduce the well proximity effect and/or the dual CESL boundary effect.
It is noted that the dummy patterns 220 and 230 described above in conjunction with
In some embodiments, the dummy patterns 340 include OD dummy patterns, gate dummy patterns, well dummy patterns, other dummy patterns, or combinations thereof. In the embodiment shown in
Conversely, each channel of the transistors of embodiments of this application face at least one of the dummy structures exemplarily described above in conjunction with
In the embodiment for forming the integrated circuit 100 described above in conjunction with
In some embodiments, the dummy patterns 221a-227a, 221b-226b, 231a-237a, and 231b-237b are formed over and/or within a substrate (not shown). The substrate may include an elementary semiconductor material, a compound semiconductor material, an alloy semiconductor material, or any other suitable material or combinations thereof. The elementary semiconductor material includes silicon or germanium in crystal, polycrystalline, or an amorphous structure. The compound semiconductor material includes silicon carbide, gallium arsenide, gallium phosphide, indium phosphide, indium arsenide, and indium antimonide. The alloy semiconductor material includes SiGe, GaAsP, AlInAs, AlGaAs, GaInAs, GaInP, and GaInAsP. In one embodiment, the alloy semiconductor substrate may have a gradient SiGe feature in which the Si and Ge composition change from one ratio at one location to another ratio at another location. In another embodiment, the alloy SiGe is formed over a silicon substrate. In another embodiment, a SiGe substrate is strained. Furthermore, the semiconductor substrate may be a semiconductor on insulator, such as a silicon on insulator (SOI), or a thin film transistor (TFT). In some examples, the semiconductor substrate may include a doped epitaxial layer or a buried layer. In other examples, the compound semiconductor substrate may have a multilayer structure, or the substrate may include a multilayer compound semiconductor structure.
In some embodiments, the OD dummy patterns 221a-227a and 231a-237a and the OD patterns of the transistors 210-217 are defined over the substrate. The OD dummy patterns 221a-227a and 231a-237a and the OD patterns of the transistors 210-217 are surrounded by an isolation material (not shown). The isolation material electrically isolates two neighboring OD patterns of the transistors 210-217 in the core area 110. The isolation material includes a shallow trench isolation (STI) structure, a local oxidation of silicon (LOCOS) structure, other isolation structure, or any combination thereof. The isolation material is formed, for example, by an STI process, a LOCOS process, or combinations thereof.
In some embodiments, dummy well patterns (not shown) and well patterns of the transistors 210-217 are defined over or within the substrate. Defining the dummy well patterns and well patterns of the transistors 210-217 is performed before or after the formation of the OD dummy patterns 221a-227a and 231a-237a and the OD patterns of the transistors 210-217. In some embodiments, the dummy well patterns and well patterns of the transistors 210-217 are formed by any suitable process, such as ion implantation and/or a rapid thermal process (RTP) to activate the doped regions.
In some embodiments, the dummy gate patterns 221b-226b and 231b-237b and the gate electrodes of the transistors 210-217 are formed over the substrate. The dummy gate patterns 221b-226b and 231b-237b and the gate electrodes of the transistors 210-217 include one or more materials including polysilicon, Ti, TiN, TaN, Ta, TaC, TaSiN, W, WN, MoN, MoON, RuO2, and/or other suitable materials. The dummy gate patterns 221b-226b and 231b-237b and the gate electrodes of the transistors 210-217 may include one or more layers formed by physical vapor deposition (PVD), CVD, ALD, plating, and/or other suitable processes. The deposition layer is defined by, e.g., photolithographic process and/or etch process for forming the dummy gate patterns 221b-226b and 231b-237b and the gate electrodes of the transistors 210-217.
In other embodiments, the dummy gate patterns 221b-226b and 231b-237b and/or the gate electrodes of the transistors 210-217 include a work function metal layer such that it provides an N-metal work function or P-metal work function of a metal gate. P-type work function materials include compositions such as ruthenium, palladium, platinum, cobalt, nickel, and conductive metal oxides, and/or other suitable materials. N-type metal materials include compositions such as hafnium, zirconium, titanium, tantalum, aluminum, metal carbides (e.g., hafnium carbide, zirconium carbide, titanium carbide, aluminum carbide), aluminides, and/or other suitable materials.
In some embodiments, at least one gate dielectric (not shown) is formed between the OD patterns and the gate electrodes of the transistors 210-217. The gate dielectric includes a single layer or a multi-layer structure. In embodiments having a multi-layer structure, the gate dielectric includes an interfacial dielectric layer and a high-k dielectric layer. The interfacial dielectric layer may be formed by any suitable process and any suitable thickness. For example, the interfacial dielectric layer may include a material such as silicon oxide, silicon nitride, silicon oxynitride, other gate dielectric materials, and/or combinations thereof. The interfacial dielectric layer is formed, in one or more embodiments, by thermal processes, CVD processes, ALD processes, epitaxial processes, and/or combinations thereof.
The high-k dielectric layer is formed, in some embodiments, over the interfacial layer. The high-k dielectric layer includes high-k dielectric materials such as HfO2, HfSiO, HfSiON, HfTaO, HfTiO, HfZrO, other suitable high-k dielectric materials, and/or combinations thereof. The high-k material may further be selected from metal oxides, metal nitrides, metal silicates, transition metal-oxides, transition metal-nitrides, transition metal-silicates, oxynitrides of metals, metal aluminates, zirconium silicate, zirconium aluminate, silicon oxide, silicon nitride, silicon oxynitride, zirconium oxide, titanium oxide, aluminum oxide, hafnium dioxide-alumina alloy, other suitable materials, and/or combinations thereof. The high-k dielectric layer may be formed by any suitable process, such as ALD, CVD, PVD, RPCVD, PECVD, MOCVD, sputtering, plating, other suitable processes, and/or combinations thereof.
In some embodiments, source/drain (S/D) regions of the transistors 210-217 are formed in the OD patterns of the transistors 210-217. For example, at least one ion implantation process is performed for implanting ions in the source/drain regions of the transistors 210-217. The S/D regions are N-type S/D regions or p-type S/D regions. The n-type S/D regions have dopants such as Arsenic (As), Phosphorus (P), other group V element, or the combinations thereof. The p-type S/D regions have dopants such as Boron (B) or other group III element. In embodiments, a thermal process and/or rapid thermal process (RTP) is/are performed after the ion implantation processes.
In some embodiments, dielectric materials, via plugs, metallic regions, and/or metallic lines are formed over the gate electrodes of the transistors 210-217 for interconnection. The dielectric layers may include materials such as silicon oxide, silicon nitride, silicon oxynitride, low-k dielectric material, ultra low-k dielectric material, or any combinations thereof. The via plugs, metallic regions, and/or metallic lines include materials such as tungsten, aluminum, copper, titanium, tantalum, titanium nitride, tantalum nitride, nickel silicide, cobalt silicide, other proper conductive materials, and/or combinations thereof. The via plugs, metallic regions, and/or metallic lines are formed by any suitable processes, such as deposition, photolithography, and etching processes, and/or combinations thereof.
It is noted that the method 500 of forming the integrated circuit including the dummy structures described above in conjunction with
In the embodiment forming the integrated circuit 100 described above in conjunction with
In some embodiments, the system 600 including the integrated circuit 602 includes an entire system in one IC, so-called system-on-chip (SOC) or system-on-integrated-circuit (SOIC) devices. These SOC/SOIC devices provide, for example, all of the circuitry needed to implement a cell phone, personal data assistant (PDA), digital VCR, digital camcorder, digital camera, MP3 player, or the like in a single integrated circuit.
Form the foregoing description, a first embodiment of this application provides an integrated circuit including dummy structures. The integrated circuit includes a core area. The core area has at least one edge region. A plurality of transistors are disposed in the edge region. A plurality of dummy structures are disposed adjacent to the at least one edge region. Each channel of the transistors in a channel width direction faces at least one of the dummy structures.
In a second embodiment, a method for forming an integrated circuit includes forming a plurality of dummy structures. The dummy structures are disposed adjacent to at least one edge region of a core area of the integrated circuit. A plurality of transistors are formed and disposed in the at least one edge region of the core area. Each channel of the transistors in a channel width direction faces at least one of the dummy structures.
The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
Claims
1. An integrated circuit, comprising:
- a boundary region comprising an input/output circuit;
- a core area comprising functional elements of the integrated circuit located exclusively in the core area, the boundary region and the core area defining an edge separating, in plan view, the boundary region and the core area;
- a plurality of transistors disposed in the core area and adjacent to the edge, the plurality of transistors being functional elements of the integrated circuit; and
- a plurality of first gate dummy structures disposed in the boundary region and adjacent to the edge, wherein each transistor of the plurality of transistors comprises a channel having a channel width direction substantially perpendicular to the edge, each channel of the plurality of transistors is aligned with a corresponding first gate dummy structure of the plurality of first gate dummy structures along the channel width direction without an intervening dummy structure therebetween, each element of the boundary region adjacent the edge is a first gate dummy structure of the plurality of first gate dummy structures; and
- a plurality of second gate dummy structures, wherein an entirety of each second gate dummy structure of the plurality of second gate dummy structures is farther from the edge than each first gate dummy structure of the plurality of first gate dummy structures, and each second gate dummy structure of the plurality of second gate dummy structures and each first gate dummy structure of the plurality of first gate dummy structures is aligned with a channel of a corresponding transistor of the plurality of transistors in an alternating fashion.
2. The integrated circuit of claim 1, further comprising a plurality of oxide definition (OD) dummy patterns, wherein each OD dummy pattern of the plurality of OD dummy patterns is between adjacent first gate patterns of the plurality of first gate patterns.
3. The integrated circuit of claim 1, further comprising:
- a plurality of third dummy patterns, wherein the third dummy patterns are disposed in the core area, between two of the plurality of transistors, and substantially aligned with the first gate dummy patterns along the channel width direction.
4. The integrated circuit of claim 3, wherein the third dummy patterns include at least one selected from the group consisting of oxide definition (OD) dummy patterns, well dummy patterns, gate dummy patterns, and metal dummy patterns.
5. The integrated circuit of claim 1, further comprising:
- a plurality of fourth dummy patterns, wherein the fourth dummy patterns are disposed adjacent to the second gate dummy patterns and misaligned, along the channel width direction, from the second gate dummy patterns.
6. The integrated circuit of claim 5, wherein the fourth dummy patterns include at least one selected from the group consisting of oxide definition (OD) dummy patterns, well dummy patterns, gate dummy patterns, and metal dummy patterns.
7. The integrated circuit of claim 1, each transistor of the plurality of transistors further comprises an OD pattern by which the channel thereof is defined.
8. An integrated circuit, comprising:
- a boundary region comprising an input/output circuit;
- a core area comprising functional elements of the integrated circuit located exclusively in the core area, the boundary region and the core area defining an edge separating, in plan view, the boundary region and the core area;
- a plurality of transistors disposed in the core area and adjacent to the edge, the plurality of transistors being functional elements of the integrated circuit;
- a plurality of first oxide definition (OD) dummy patterns disposed in the boundary region and adjacent to the edge, wherein adjacent first OD dummy patterns are defined on opposite sides of a first dummy gate; and
- a plurality of second OD dummy patterns that are disposed in the boundary region, wherein adjacent second OD dummy patterns are defined on opposite sides of a second dummy gate, the plurality of first OD dummy patterns are closer to the edge than the plurality of second OD dummy patterns, and the plurality of second OD dummy patterns misaligned, along a direction perpendicular to the edge, from the plurality of first OD dummy patterns,
- and a center of each second OD dummy pattern of the plurality of second OD dummy patterns and a center of each first OD dummy pattern of the plurality of first OD dummy patterns is aligned with a channel of a corresponding transistor of the plurality of transistors in an alternating fashion.
9. The integrated circuit of claim 8, further comprising:
- a plurality of third OD dummy patterns, wherein each third OD dummy pattern of the third OD dummy patterns is disposed in the core area, between two of the transistors, and substantially aligned with a corresponding first OD dummy pattern of the plurality of first OD dummy patterns along the direction.
10. The integrated circuit of claim 8, further comprising:
- a plurality of fourth OD dummy patterns, wherein each fourth OD dummy pattern of the fourth OD dummy patterns is disposed adjacent to corresponding second OD dummy patterns of the plurality of second OD dummy patterns and misaligned from the second OD dummy patterns along the direction.
11. The integrated circuit of claim 8, further comprising:
- a plurality of first gate dummy patterns, wherein each of the first gate dummy patterns is disposed between two of the first OD dummy patterns.
12. The integrated circuit of claim 11, further comprising:
- a plurality of second gate dummy patterns, wherein each of the second gate dummy patterns is disposed between two of the second OD dummy patterns.
13. An integrated circuit, comprising:
- a boundary region comprising an input/output circuit;
- a core area comprising functional elements of the integrated circuit located exclusively in the core area, the boundary region and the core area defining an edge separating, in plan view, the boundary region and the core area;
- a plurality of transistors disposed in the core area and adjacent to the edge, the plurality of transistors being functional elements of the integrated circuit;
- a plurality of first gate dummy patterns disposed in the boundary region and adjacent to the edge, wherein a channel of every transistor of the plurality of transistors in the core area adjacent to the boundary region is aligned with a corresponding gate dummy pattern of the plurality of first gate dummy patterns along a channel width direction without an intervening dummy pattern therebetween; and
- a plurality of second dummy patterns disposed in the core area and between a transistor of the plurality of transistors and a single active transistor, wherein the single active transistor is the only active transistor between a periphery of the core region and the plurality of second dummy patterns, and a gate of each dummy pattern of the plurality of second dummy patterns is substantially aligned with a corresponding gate dummy pattern of the plurality of first gate dummy patterns along the channel width direction without an intervening active transistor.
14. The integrated circuit of claim 13, further comprising a plurality of oxide definition (OD) dummy patterns, wherein each OD dummy pattern of the plurality of OD dummy patterns is between adjacent first gate patterns of the plurality of first gate patterns.
15. The integrated circuit of claim 13,
- further comprising:
- first oxide definition (OD) dummy patterns disposed in the boundary region, wherein a pair of adjacent first OD dummy patterns sandwich one of the first gate dummy patterns therebetween; and
- second OD dummy patterns disposed in the core area and between two of the transistors, wherein a pair of adjacent second OD dummy patterns sandwich one of the second gate dummy patterns therebetween.
16. The integrated circuit of claim 15, wherein
- each transistor of the plurality of transistors further comprises an OD pattern by which the channel thereof is defined.
17. The integrated circuit of claim 16, wherein a width of each of the OD patterns of the plurality of transistors in the channel width direction is smaller than that of each of the first and second OD dummy patterns.
18. The integrated circuit of claim 15, wherein each of the second OD dummy patterns is substantially aligned with one of the first OD dummy patterns along the channel width direction.
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Type: Grant
Filed: Mar 17, 2010
Date of Patent: May 9, 2017
Patent Publication Number: 20110227188
Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.
Inventors: Chien-Hsun Wang (Hsinchu), Chih-Sheng Chang (Hsinchu), Hsien-Hui Meng (Taipei)
Primary Examiner: Ori Nadav
Application Number: 12/726,309
International Classification: H01L 29/06 (20060101); H01L 27/02 (20060101); H01L 27/092 (20060101); H01L 27/105 (20060101);